Infants with short gut remain TPN-dependent for prolonged periods of time and frequently develop TPN-associated liver disease which complicates their course further. Except for bowel lengthening (Bianchi procdure) and bowel transplantation, little can be offered to these patients. Human growth hormone (GH) has been shown to potentiate protein anabolism associated with total parenteral alimentation (TPN) in adult patients, and improved nutrient absorption in adults with short gut and in several animal models (1-3). Whether this agent would be of similart benefit in infants is not known. One specific aim of this project is to define the metabolic actions of GH, when used in conjunction with PTN, with specific reference to the following: protein (whole body protein synthesis and proteolysis); carbohydrate (hepatic glucose production and glucose disposal); and fat (lipolysis). The second specific aim is to define the effect of 3-month's treatment with GH on the following: body growth and composition (height and weight, DEXA scanning, skinfold thicknesses); gut tissue and function (fat and carbohydrate absorption studies, small bowel biopsies for anatomical and pathologic examination); and morbidity, duration of hospital stay.